<%--
  Created by IntelliJ IDEA.
  User: jb9
  Date: 2018/2/27
  Time: 14:31
  To change this template use File | Settings | File Templates.
--%>
<%@ page import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*"%>
<%@ page import="java.io.OutputStream"%>
<%!Color getRandColor(int fc, int bc) {
    Random random = new Random();
    if (fc > 255)
        fc = 255;
    if (bc > 255)
        bc = 255;
    int r = fc + random.nextInt(bc - fc);
    int g = fc + random.nextInt(bc - fc);
    int b = fc + random.nextInt(bc - fc);
    return new Color(r, g, b);
}%>
<%
    try {
        response.setHeader("Pragma", "No-cache");
        response.setHeader("Cache-Control", "no-cache");
        response.setDateHeader("Expires", 0);
        int width = 110, height = 20;
        BufferedImage image = new BufferedImage(width, height,
                BufferedImage.TYPE_INT_RGB);
        OutputStream os = response.getOutputStream();
        Graphics g = image.getGraphics();
        Random random = new Random();
        g.setColor(getRandColor(200, 250));
        g.fillRect(0, 0, width, height);
        g.setFont(new Font("Times New Roman", Font.PLAIN, 18));
        g.setColor(getRandColor(160, 200));
        for (int i = 0; i < 155; i++) {
            int x = random.nextInt(width);
            int y = random.nextInt(height);
            int xl = random.nextInt(12);
            int yl = random.nextInt(12);
            g.drawLine(x, y, x + xl, y + yl);
        }
        String[] s = { "A", "B", "C", "D", "E", "F", "G", "H", "I",
                "J", "K", "L", "M", "N", "P", "Q", "R", "S", "T", "U",
                "V", "W", "X", "Y", "Z" };
        String sRand = "";
        for (int i = 0; i < 4; i++) {
            String rand = "";
            if (random.nextBoolean()) {
                rand = String.valueOf(random.nextInt(10));
            } else {
                int index = random.nextInt(25);
                rand = s[index];
            }
            sRand += rand;
            g.setColor(new Color(20 + random.nextInt(10), 20 + random.nextInt(110), 20 + random.nextInt(110)));
            g.drawString(rand, 17 * i + 6, 16);
        }
        session.setAttribute("rand", sRand);
        g.dispose();
        ImageIO.write(image, "JPEG", os);
        os.flush();
        os.close();
        os = null;
        response.flushBuffer();
        out.clear();
        out = pageContext.pushBody();
    } catch (IllegalStateException e) {
        System.out.println(e.getMessage());
        e.printStackTrace();
    }
%>
